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1.
Barlette Vania Elisabeth Garbujo Fábio Luiz Laurenti Freitas Luiz Carlos Gomide 《Molecular Engineering》1997,7(3-4):439-455
A five site potential model combining Lennard–Jones plus Coulomb potential functions has been developed for chloroform molecule.
The partial charges needed for Coulombic interactions were derived using the chelpg procedure implemented in the gaussian
92 program. These calculations were performed at the MP2 level with MC-311G* basis set for Cl and 6-311G** for C and H atoms.
The parameters for the Lennard–Jones potentials were optimized to reproduce experimental values for the density and enthalpy
of vaporization of the pure liquid at 298 K and 1 atm. The statistical mechanics calculations were performed with the Monte
Carlo method in the isothermic and isobaric (NpT) ensemble. Besides the values obtained for density, ρ, and molar enthalpy
of vaporization at constant pressure, Δ HV, for liquid chloroform, results for molar volume, Vm, molar heat capacity, Cp, isobaric thermal expansivity, αp, and isothermal compressibility, κT, for this pure liquid are also in very good agreement with experimental observations. Size effects on the values of thermodynamic
properties were investigated. The potential model was also tested by computing the free energy for solvating one chloroform
molecule into its own liquid at 298 K using a statistical perturbation approach. The result obtained compares well with the
experimental value. Site–site pair correlation functions were calculated and are in good accordance with theoretical results
available in the literature. Dipole–dipole correlation functions for the present five site model were also calculated at different
carbon–carbon distances. These correlations were compared to those obtained using the four site model reported in the literature.
An investigation of the solvent dependence of the relative free energy for cis/trans conversion of a hypothetical solute in
TIP4P water and chloroform was accomplished. The results show strong interaction of water and chloroform molecules with the
gauche conformer. The value obtained for the free energy barrier for cis/trans rotation in TIP4P water is higher than that
for chloroform. This result is in agreement with the continuous theory for solvation as the conformer with higher dipole moment
is more favoured by the solvent with higher dieletric constant. The results also show an increase in entropy as the solute
goes from the cis to the trans geometry and this result is more appreciable in the aqueous solution.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
2.
3.
Jennifer C. Erasmus Kasia Smolarczyk Helena Brezovjakova Noor F. Mohd-Naim Encarnacin Lozano Karl Matter Vania M.M. Braga 《The Journal of cell biology》2021,220(6)
Rac1 GTPase is hyperactivated in tumors and contributes to malignancy. Rac1 disruption of junctions requires its effector PAK1, but the precise mechanisms are unknown. Here, we show that E-cadherin is internalized via micropinocytosis in a PAK1–dependent manner without catenin dissociation and degradation. In addition to internalization, PAK1 regulates E-cadherin transport by fine-tuning Rab small GTPase function. PAK1 phosphorylates a core Rab regulator, RabGDIβ, but not RabGDIα. Phosphorylated RabGDIβ preferentially associates with Rab5 and Rab11, which is predicted to promote Rab retrieval from membranes. Consistent with this hypothesis, Rab11 is activated by Rac1, and inhibition of Rab11 function partially rescues E-cadherin destabilization. Thus, Rac1 activation reduces surface cadherin levels as a net result of higher bulk flow of membrane uptake that counteracts Rab11-dependent E-cadherin delivery to junctions (recycling and/or exocytosis). This unique small GTPase crosstalk has an impact on Rac1 and PAK1 regulation of membrane remodeling during epithelial dedifferentiation, adhesion, and motility. 相似文献
4.
Patrone Vania Al-Surrayai Tahani Romaniello Francesco Fontana Alessandra Milani Giovanni Sagheddu Valeria Puglisi Edoardo Callegari Maria Luisa Al-Mansour Hamad Kishk Mohamed Waheed Morelli Lorenzo 《Probiotics and antimicrobial proteins》2021,13(3):809-823
Probiotics and Antimicrobial Proteins - Probiotics represent a possible strategy for controlling intestinal infections in livestock. Members of the Weissella genus are increasingly being studied... 相似文献
5.
Vania Rebolledo María Carolina Otero Jos Manuel Delgado Fernando Torres Michelle Herrera Miguel Ríos Mauricio Cabaas Jos L. Martinez Mait Rodríguez-Díaz 《Saudi Journal of Biological Sciences》2021,28(1):1052
The Andean tree Schinus areira L. has multiple traditional uses, from the treatment of bronchitis and rheumatic diseases to menstrual cycle regulation and wound healing. With reported hypotensive, analgesic, antitumoral and anti-inflammatory properties, it acts predominantly against diseases related to oxidative stress. This study focuses on the antioxidant activity and phytochemical profile of the extracts of Schinus areira L.Serial extraction of the fruits was performed both by maceration and by Soxhlet. Total phenols and flavonoids were measured using the Folin-Ciocalteu method and AlCl3, respectively. In vitro antioxidant activity was determined by FRAP and DPPH.Results were similar for both extraction methods. Primary metabolites detected included carbohydrates, proteins and amino acids; secondary metabolites included tannins, flavonoids, saponins, steroids and triterpenes. Antioxidant activity was confirmed for ethyl acetate, methanolic and aqueous extracts. The methanolic extract had both the highest polyphenol content (>195 mg GAE/ g dry weight) and the highest antioxidant activity [EC50 > 476 μg/mL; >273 mg AA/g dry weight (DPPH); >301 mg AA/ g dry weight (FRAP)]. The extract does not produce macrophage cytotoxicity in RAW 264.7, which is indicated by an average cytotoxicity of 2% over 24 h.Our study serves as a starting point for future research on the pharmacological properties of Schinus areira L. 相似文献
6.
7.
Jeremie Boyer Vania Bernardes-Genisson Vincent Farines Jean-Pierre Souchard Francoise Nepveu 《Free radical research》2013,47(5):459-471
A series of 2-alkyl and 2-aryl substituted-3H-indol-3-one-1-oxides was prepared and evaluated for its radical trapping properties. Spin trapping and electron paramagnetic resonance experiments demonstrate the ability of these indolone-1-oxides to trap hetero- and carbon-centered radicals. The most stable spin adducts (lifetime of several hours) are obtained with 2-alkyl substituted nitrones, the 2-ethyl-5,6-dioxolo-3H-indolone-1-oxide, 5e and the 2-secbutyl-3H-indolone-1-oxide, 5f. These two nitrones are also sensitive to redox reactions in solution. Therefore this indolone-1-oxide series lacking a β-hydrogen atom gives rise to highly stable adducts with free radicals. 相似文献
8.
Afshin Salimeh Mustafa Mohammadi Bahman Rashidi 《Journal of physiology and biochemistry》2013,69(2):255-265
This study was aimed to evaluate the preventive effect of diosgenin and exercise on tissue antioxidant status in isoproterenol-induced myocardial infarction (MI) in male Wistar rats. Levels of lipid peroxides, reduced glutathione (GSH), and the activities of glutathione-dependent antioxidant enzymes (glutathione peroxidise and glutathione reductase) and antiperoxidative enzymes (catalase and superoxide dismutase) in the plasma and the heart tissue of experimental groups of rats were determined. Pretreatment with diosgenin and exercise exerted an antioxidant effect against isoproterenol-induced myocardial infarction by blocking the induction of lipid peroxidation. A tendency to prevent the isoproterenol-induced alterations in the level of GSH, in the activities of glutathione-dependent antioxidant enzymes and antiperoxidative enzymes was also observed. Histopathological findings of the myocardial tissue showed a protective role for combination of diosgenin and exercise in isoproterenol (ISO)-treated rats. Thus, the present study reveals that preconditioning with diosgenin and exercise exerts cardioprotective effect against ISO-induced MI due to its free radical scavenging and antioxidant effects, which maintains the tissue defense system against myocardial damage. 相似文献
9.
Raquel Schier Guerra Mariana Machado Fidelis do Nascimento Stephanie Miesch Mohammad Javad Najafzadeh Raphael Orélis Ribeiro Antonio Ostrensky Gerrit Sybren de Hoog Vania Aparecida Vicente Walter A. Boeger 《Mycopathologia》2013,175(5-6):421-430
Knowledge of natural ecology is essential for a better understanding of pathogenicity and opportunism in black yeast-like fungi. Although etiological agents of diseases caused by these fungi are supposed to originate from the environment, their isolation from nature is difficult. This is probably due to their oligotrophic nature, low competitive ability, and, overall, insufficient data on their natural habitat. We obtained environmental samples from mangrove areas where mortalities by lethargic crab disease (LCD) are reported and areas without disease recorded. Isolation of chaetothyrialean black yeasts and relatives was performed using a highly selective protocol. Species-specific primers were used to determine if these isolates represented Exophiala cancerae or Fonsecaea brasiliensis, two proven agents of LCD, in order to test hypotheses about the origin of the disease. Isolates, identified by morphology as Fonsecaea- or Exophiala-like, were tested specific diagnostic markers for the fungi associated with LCD. Although several black fungi were isolated, the main causative agent of the LCD, E. cancerae, was not found. Molecular markers for F. brasiliensis revealed 10 positive bands for isolates from biofilms on mangrove leaves, branches, and aerial roots, of which four were confirmed by ITS sequencing. The absence of E. cancerae in environmental samples suggests that the species is dependent on the crab, as a genuine pathogen, different from F. brasiliensis, which is probably not dependent on the host species, U. cordatus. However, we did not attempt isolation from the marine water, which may represent the pathway of dispersion of the black yeast species between neighbor mangroves. 相似文献
10.
Stanley J. Bolanowski Lisa M. Maxfield George A. Gescheider A. Vania Apkarian 《Somatosensory & motor research》2013,30(2):195-204
The influence of heat- and cold-induced pain on tactile sensitivity, a "touch gate", was measured under conditions in which the location of the noxious stimuli was varied with respect to the tactile stimulus applied to the thenar eminence of humans. Vibrotactile thresholds were measured in the absence of pain and during administration of a painful stimulus, with the stimulus frequencies selected to activate independently the four psychophysical channels hypothesized to exist in human glabrous skin. Heat-induced pain produced by spatially co-localizing the noxious stimuli with the tactile stimuli was found, on average, to elevate threshold amplitude by 2.2 times (6.7 dB). Co-localized, cold-induced pain raised the average thresholds by about 1.5 times (3.6 dB). Heat-induced pain presented contralaterally produced no change in vibrotactile sensitivity indicating that the effect is probably not due to attentional mechanisms. Ipsilateral heat-induced pain caused an elevation in tactile thresholds even when the noxious and non-noxious stimuli were not co-localized, and the effect may seem to require that the painful stimulus be within the somatosensory region defined possibly in terms of dermatomal organization. Thus the effect is probably related to somatotopic organization and is not peripherally mediated. A brief discussion as to the possible locus of the touch gate within the nervous system is also given. 相似文献